**QUICK ASK**HUMAN SKELETON

Human Body/Skeleton

From Wikibooks, the open-content textbooks collection

The skeleton is the part of our body that allows it to keep its shape. It is made up of hundreds of connected bones, each with a different rol

A diagram of the human skeleton

An adult skeleton system has 206 bones. The longest is the thigh bone - femur The smallest inside the ear - ossicles.

Functions of the Skeleton

The skeleton has six main functions:

• Support - the skeleton is the 'frame' which supports the body, allowing us to maintain our shape.
• Attachment - muscles, tendons and ligaments attach to the surface of the bones.
• Movement - skeletal muscles allow us to move around and these are attached to the skeleton by tendons. If it were not for the skeleton, movement would be much harder and would be very restricted.
• Protection - the skeleton protects most of the vital organs. For example the skull protects the brain and the ribcage protects the lungs and the heart.
• Blood cell production - blood cells are made inside bone marrow, which is found in bones of the skeleton.

Structure of the Skeleton

Bones contain blood vessels , nerve cells and living bones. A non-living hard matter of calcium and phosphorous protects these.

Skeleton joints

Joints are the meeting point of bones. These restrict as well as facilitate movement of bones. Fixed joint , movable joints , ball and socket joints , pivot joints, etc., are different types of joints.

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**QUICK ASK**WHAT IS MUSCLE-

Muscles are the organs that make us move. Muscles are everywhere. They can be tiny as in the ear or huge like leg muscles. Although no muscle is directly visible you can watch many of them in action in the mirror, when you flex your muscles.

What does a muscle look like?

A muscle is usually a long round organ. The color is red. A muscle is flexible and shortens and thickens during a contraction. The figure on the right shows a series of magnifications of a muscle. You can see that a muscle is a collection of fibres or strings, each of which is capable of contraction. The added force of these fibres is the strength of the muscle.

What are the parts of a muscle?

A muscle has two ends each of which attach to some other organ, usually a bone. These connectors are called tendons.

What is the function of a muscle?

Muscles produce almost all movements in our body. We need healthy muscles to be able to walk, move, and even smile. The muscles in our heart move blood around the body. Without muscles, we couldn't live.

How does a muscle interact with other parts of the body?

Muscles connect with all of the other parts of the body. Muscles in the heart pump blood throughout the body. The diaphragm is a large muscle that allows us to breathe. Muscles from our mouth to our stomach and beyond help us swallow food and move it through the digestive system. Even our eyes have muscles that let us look around and see our surroundings.

How can you keep your muscles healthy?

Our muscles are kept healthy through regular exercise. Eating properly and especially including protein in your diet will help keep your muscles healthy.

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Thigh to Foot Musculature

Muscle Regions of the Body:

• Head and neck
• Trunk, front and back
• Brachium, antibrachium & hand
• Thigh, leg & foot

Return to the Muscle Starting Point  Muscle Groups within this Region:

• Gluteal
• Posterior Thigh
• Adductor Thigh
• Anterior Thigh
• Posterior Leg
• Anterolateral Leg
• Foot

Links Related to this Region:

• Normal Distal Thigh Anatomy I (from UW)
• Normal Distal Thigh Anatomy II (from UW)
• Normal Knee Anatomy (from UW)
• Iliotibial Band Syndrome
• Hallux Valgus Tutorial (from UW)

Gluteal Musculature

 

Tensor fascia lata

• Origin:
  
  
  1. anterior aspect of iliac crest
  2. anterior superior iliac spine (ASIS)
• Insertion: anterior aspect of IT band, below greater trochanter
• Action:
  
  
  1. hip flexion
  2. medially rotate & abduct a flexed thigh
  3. tenses IT tract to support femur on the tibia during standing
• Blood:
  
  
  1. superior gluteal artery
  2. lateral femoral circumflex artery
• Nerve: superior gluteal nerve, L4,5,S1

Gluteus maximus

• Origin:
  
  
  1. outer rim of ilium (medial aspect)
  2. dorsal surface of sacrum and coccyx
  3. sacrotuberous ligament
• Insertion:
  
  
  1. IT band (primary insertion)
  2. gluteal tuberosity of femur
• Action:
  
  
  1. powerful extensor of hip
  2. laterally rotates thigh
  3. upper fibers aid in abduction of thigh
  4. fibers of IT band stabilize a fully extended knee
• Blood:
  
  
  1. inferior gluteal artery (primary)
  2. superior gluteal artery
• Nerve: inferior gluteal nerve, L5,S1,2

Gluteus medius

• Origin:
  
  
  1. outer aspect of ilium (between iliac crest and anterior and posterior gluteal lines)
  2. upper fascia (AKA gluteal aponeurosis)
• Insertion: superior aspect of greater trochanter
• Action:
  
  
  1. anterior and lateral fibers abduct and medially rotate the thigh
  2. posterior fibers may laterally rotate thigh
  3. stabilizes the pelvis and prevents free limb from sagging during gait
• Blood: superior gluteal artery
• Nerve: superior gluteal nerve, L4,5,S1

Gluteus minimus

• Origin: outer aspect of ilium (between anterior and inferior gluteal lines)
• Insertion:
  
  
  1. greater trochanter (anterior to medius)
  2. articular capsule of hip joint
• Action:
  
  
  1. abduct and medially rotate the thigh
  2. stabilizes the pelvis and prevents free limb from sagging during gait
• Blood: superior gluteal artery
• Nerve: superior gluteal nerve, L4,5,S1

Piriformis

• Origin: pelvic surface of sacrum (anterior portion)
• Insertion: medial surface of greater trochanter (through greater sciatic foramen)
• Action:
  
  
  1. lateral rotation of extended thigh
  2. abducts a flexed thigh
• Blood:
  
  
  1. superior gluteal artery
  2. inferior gluteal artery
• Nerve: nerve to piriformis, S1,2

Superior gemellus

• Origin: ischial spine
• Insertion: medial aspect of greater trochanter via upper tendon of obturator internus
• Action:
  
  
  1. laterally rotates femur
  2. abducts thigh when flexed
• Blood: inferior gluteal artery
• Nerve: nerve to obturator internus, L5,S1,2

Obturator internus

• Origin:
  
  
  1. internal aspect margins of obturator foramen
  2. obturator membrane
• Insertion: medial aspect of greater trochanter (through lesser sciatic foramen)
• Action:
  
  
  1. laterally rotates femur
  2. abducts thigh when flexed
• Blood: inferior gluteal artery
• Nerve: nerve to obturator internus, L5,S1,2

Inferior gemellus

• Origin: ischial tuberosity
• Insertion: medial aspect of greater trochanter via lower tendon of obturator internus
• Action: laterally rotates femur
• Blood: inferior gluteal artery
• Nerve: nerve to quadratus femoris, L4,5,S1

Quadratus femoris

• Origin: lateral aspect of ischial tuberosity
• Insertion: quadrate line (along posterior aspect of femur and intertrochanteric crest)
• Action: laterally rotates femur
• Blood: inferior gluteal artery
• Nerve: nerve to quadratus femoris, L4,5,S1

Posterior Thigh Musculature

 

Semitendinosus

• Origin: ischial tuberosity
• Insertion:
  
  
  1. medial aspect of tibial shaft
  2. contributes to the pez anserine
• Action:
  
  
  1. extends hip
  2. flexes knee
  3. medially rotates tibia
• Blood:
  
  
  1. perforating branches of profunda femoris
  2. inferior gluteal artery (to upper)
• Nerve: tibial nerve of sciatic bundle, L5,S1,2

Semimembranosus

• Origin: ischial tuberosity
• Insertion:
  
  
  1. posterior medial aspect of medial tibial condyle
  2. fibers join to form most of oblique popliteal ligament (& medial meniscus)
• Action:
  
  
  1. flexes knee
  2. extends hip
  3. medially rotates tibia
  4. pulls medial meniscus posterior during flexion
• Blood:
  
  
  1. perforating branches of profunda femoris
  2. inferior gluteal artery (to upper)
• Nerve: tibial nerve of sciatic bundle, L5,S1,2

Biceps femoris

• Origin:
  
  
  1. long head: ischial tuberosity
  2. short head: lateral lip of linea aspera and the lateral intermuscular septum
• Insertion:
  
  
  1. head of fibula
  2. maybe to the lateral tibial condyle
• Action:
  
  
  1. flexor at the knee (mainly short head)
  2. laterally rotates thigh if flexed at the knee
  3. extends hip (long head)
• Blood:
  
  
  1. perforating branches of profunda femoris
  2. inferior gluteal artery (to upper)
• Nerve:
  
  
  1. long head - tibial nerve, L5,S1,2
  2. short head - common peroneal nerve, L5,S1

Adductor magnus, posterior fibers are sometimes considered part of this group. Its information is listed below with the other thigh adductors.

Adductor Thigh Musculature

 

Note: The muscles in this group may also receive blood from obturator artery. Adductor longus

• Origin: anterior surface of pubis, just inferior to the pubic tubercle
• Insertion: medial lip of linea aspera on middle half of femur
• Action:
  
  
  1. adducts thigh
  2. flexes thigh
  3. may laterally rotate thigh at the hip
• Blood: muscular branches of femoral artery
• Nerve: obturator nerve, L2,3,4

Adductor brevis

• Origin: body & inferior ramus of pubis
• Insertion: superior portion of linea aspera
• Action:
  
  
  1. adducts thigh (major)
  2. aids in flexion of thigh
  3. may laterally rotate thigh at the hip
• Blood: muscular branches of femoral artery
• Nerve: obturator nerve, L2,3,4

Adductor magnus

• Origin:
  
  
  1. anterior fibers: inferior pubic ramus
  2. oblique fibers: ischial ramus
  3. posterior fibers: ischial tuberosity
• Insertion:
  
  
  1. proximal 1/3 of linea aspera
  2. adductor tubercle
• Action:
  
  
  1. adducts the thigh
  2. posterior fibers also extend and laterally rotate thigh
• Blood:
  
  
  1. muscular branches of profunda femoris
• Nerve:
  
  
  1. anterior fibers: obturator nerve, L2,3,4
  2. posterior fibers: tibial nerve of sciatic bundle, L4,5

Gracilis

• Origin: body of pubis & inferior pubic ramus
• Insertion:
  
  
  1. medial surface of proximal tibia, inferior to tibial condyle
  2. contributes to the pez anserine
• Action:
  
  
  1. adducts thigh
  2. flexes knee
  3. medially rotates tibia
• Blood: obturator artery
• Nerve: obturator nerve, L2,3,4

Obturator externus

• Origin:
  
  
  1. medial surface of obturator foramen
  2. external surface of obturator membrane
• Insertion: trochanteric fossa of femur
• Action:
  
  
  1. laterally rotates thigh
  2. assists in flexion of hip joint
• Blood: obturator artery
• Nerve: obturator nerve, L2,3,4

Anterior Thigh Musculature

 

Sartorius

• Origin: anterior superior iliac spine (ASIS)
• Insertion:
  
  
  1. upper medial surface of body of tibia
  2. contributes to pez anserine
• Action:
  
  
  1. flexes hip and knee
  2. laterally rotates thigh if flexed at the hip
• Blood:
  
  
  1. muscular branches of profunda femoris artery
  2. saphenous branch of descending genicular artery
• Nerve: branches of femoral nerve, L2,3

Rectus femoris

• Origin:
  
  
  1. anterior head: anterior inferior iliac spine (AIIS)
  2. posterior head: ilium just above the acetabulum
• Insertion:
  
  
  1. common quadriceps tendon into patella
  2. tibial tuberosity via patellar ligament
• Action:
  
  
  1. extends knee
  2. flexes hip
• Blood: lateral femoral circumflex artery
• Nerve: branches of femoral nerve, [L2],3,4

Vastus lateralis

• Origin:
  
  
  1. greater trochanter
  2. lateral lip of linea aspera
  3. lateral intermuscular septum
• Insertion:
  
  
  1. common quadriceps tendon into patella
  2. tibial tuberosity via patellar ligament
• Action:
  
  
  1. extends knee
  2. can abnormally displace patella
• Blood: lateral femoral circumflex artery
• Nerve: branches of femoral nerve, [L2],3,4

Vastus intermedius

• Origin: anterior lateral aspect of the femoral shaft
• Insertion:
  
  
  1. common quadriceps tendon into patella
  2. tibial tuberosity via patellar ligament
• Action: extends knee
• Blood: lateral femoral circumflex artery
• Nerve: branches of femoral nerve, [L2],3,4

Vastus medialis

• Origin:
  
  
  1. intertrochanteric line of femur
  2. medial aspect of linea aspera
• Insertion:
  
  
  1. common quadriceps tendon into patella
  2. tibial tuberosity via patellar ligament
• Action: extends knee
• Blood:
  
  
  1. muscular branches of profunda femoris artery
  2. saphenous branch of descending genicular artery
• Nerve: branches of femoral nerve, [L2],3,4

Articularis genus

• Origin:
  
  
  1. distal portion of anterior femoral surface, close to the knee
  2. off the deep fibers of the vastus intermedius
• Insertion: synovial membrane of the knee joint
• Action:
  
  
  1. pulls the synovial membrane of the knee superior with knee extension
  2. prevents impingement of the synovial membrane between patella and the femur
• Blood: lateral femoral circumflex artery
• Nerve: branches of femoral nerve, L3,4

Psoas major

• Origin:
  
  
  1. transverse processes of L1-L5
  2. vertebral bodies of T12-L4 and the intervening intervertebral discs
• Insertion: iliopsoas tendon to the lesser trochanter of the femur
• Action:
  
  
  1. hip flexion
  2. lateral rotation
• Blood: muscular branches of medial femoral circumflex artery
• Nerve: ventral rami, L1,2,3

Illiacus

• Origin: inner surface of upper iliac fossa
• Insertion: iliopsoas tendon to the lesser trochanter of the femur
• Action:
  
  
  1. powerful hip flexion
  2. lateral rotation
• Blood: muscular branches of medial femoral circumflex artery
• Nerve: femoral nerve, L3,4

Pectineus

• Origin:
  
  
  1. pectineal line of the pubis
  2. superior pubic ramus
• Insertion:
  
  
  • the pectineal line of the femur
  • (just below the lesser trochanter on the posterior aspect of the femur)
• Action:
  
  
  1. flexes hip
  2. adducts thigh
  3. medially rotates thigh
• Blood: muscular branches of medial femoral circumflex artery
• Nerve:
  
  
  • femoral nerve, L3,4 OR
  • obturator nerve, L2,3,4 OR
  • femoral L3,4 and accessory obturator L3,4
  
  
  
  

  Posterior Leg Musculature

  
  
  
   
  Gastrocnemius
  
  
  
  • Origin:
    
    
    1. medial head: just above medial condyle of femur
    2. lateral head: just above lateral condyle of femur
  • Insertion: calcaneus via lateral portion of calcaneal tendon
  • Action:
    
    
    1. plantarflex the ankle
    2. knee flexion (when not weight bearing)
    3. stabilizes ankle & knee when standing
  • Blood:
    
    
    1. sural branches of popliteal artery
    2. muscular branches of peroneal artery
    3. posterior tibial artery
  • Nerve: tibial nerve, S1,2
  Soleus
  
  
  
  • Origin:
    
    
    1. upper fibula
    2. soleal line of tibia
  • Insertion: calcaneus via medial portion of calcaneal tendon
  • Action: plantarflex the foot
  • Blood:
    
    
    1. sural branches of popliteal artery
    2. muscular branches of peroneal artery
    3. posterior tibial artery
  • Nerve: tibial nerve, S1,2
  Plantaris
  
  
  
  • Origin: above the lateral head of gastrocnemius on femur
  • Insertion: calcaneus, medial to calcaneal tendon, or blending with the calcaneal tendon
  • Action: like a weak gastrocnemius
  • Blood:
    
    
    1. sural branches of popliteal artery
    2. muscular branches of peroneal artery
    3. posterior tibial artery
  • Nerve: tibial nerve, S1,2
  Popliteus
  
  
  
  • Origin:
    
    
    1. lateral femoral condyle
    2. arcuate popliteal ligament
    3. lateral meniscus
    4. knee joint capsule
  • Insertion: posterior tibial surface above the soleal line
  • Action:
    
    
    1. insertion fixed: laterally rotates femur on tibia & unlocks knee
    2. origin fixed: medially rotates tibia on femur & unlocks knee
  • Blood: sural branches of popliteal artery
  • Nerve: tibial nerve, L5,S1
  Flexor digitorum longus
  
  
  
  • Origin:
    
    
    1. posterior surface of tibia
    2. crural fascia
  • Insertion: plantar surface of bases of the 2-5th distal phalanges
  • Action:
    
    
    1. primarily flexes 2nd - 5th toes
    2. weak plantarflexor
    3. weak inversion & adduction of foot
  • Blood:
    
    
    1. peroneal artery
    2. posterior tibial artery
  • Nerve: tibial nerve, L5,S1
  Tibialis posterior
  
  
  
  • Origin:
    
    
    1. posterior, proximal tibia
    2. interosseous membrane
    3. medial surface of fibula
  • Insertion:
    
    
    1. navicular tuberosity (principle)
    2. all 3 cuneiforms (plantar surface)
    3. bases of 2nd-4th metatarsals
    4. cuboid
    5. sustentaculum tali of calcaneus
  • Action:
    
    
    1. stabilizes ankle
    2. inversion & adduction of foot
    3. prevents hyperpronation while in gait
    4. weak plantarflexion of ankle
  • Blood:
    
    
    1. peroneal artery
    2. posterior tibial artery
  • Nerve: tibial nerve, L5,S1
  Flexor hallucis longus
  
  
  
  • Origin:
    
    
    1. posterior, inferior 2/3 of fibula
    2. interosseous membrane
    3. crural fascia & posterior intermuscular septum
  • Insertion: plantar surface of distal phalanx of hallux
  • Action:
    
    
    1. flexes big toe (hallux)
    2. weak plantarflexion of the foot
    3. weak inversion & adduction of foot
  • Blood:
    
    
    1. peroneal artery
    2. posterior tibial artery
  • Nerve: tibial nerve, L5,S1,2
  
  
  
  

  Anterolateral Leg Musculature

  
  
  
   
  Peroneus longus
  
  
  
  • Origin:
    
    
    1. head of the fibula
    2. proximal 2/3 of lateral fibula
    3. adjacent intermuscular septum
  • Insertion:
    
    
    1. plantar surface of cuboid
    2. base of 1st & (2nd) metatarsal
    3. plantar surface of medial cuneiform
  • Action:
    
    
    1. eversion & abduction of the foot
    2. weak plantarflexion of the foot at the transverse tarsal joint
  • Blood: muscular branches of the peroneal artery
  • Nerve: superficial peroneal nerve, L4,5,S1
  Peroneus brevis
  
  
  
  • Origin:
    
    
    1. distal 2/3 of lateral fibula
    2. posterior and anterior intermuscular septum
  • Insertion: tuberosity on lateral aspect of base of 5th metatarsal
  • Action:
    
    
    1. eversion & abduction of the foot
    2. weak plantarflexion of foot
  • Blood: muscular branches of the peroneal artery
  • Nerve: superficial peroneal nerve, L4,5,S1
  Tibialis anterior
  
  
  
  • Origin:
    
    
    1. lateral tibial condyle
    2. proximal 2/3 of anteriolateral surface of tibia
    3. interosseous membrane
    4. anterior intermuscular septum & crural fascia
  • Insertion:
    
    
    1. medial & plantar surface of base of 1st metatarsal
    2. medial & plantar surface of the cuneiform
  • Action:
    
    
    1. strongest dorsiflexor
    2. inverts & adducts the foot
  • Blood: anterior tibial artery
  • Nerve: deep peroneal nerve, L4,5,S1
  Extensor hallucis longus
  
  
  
  • Origin:
    
    
    1. medial aspect of the fibula
    2. interosseous membrane
    3. crural fascia
  • Insertion: dorsal surface of base of proximal and distal phalanx of hallux
  • Action:
    
    
    1. extends distal phalanx of big toe
    2. weak dorsiflexor
    3. weak inversion & adduction
  • Blood: anterior tibial artery
  • Nerve: deep peroneal nerve, L4,5,S1
  Extensor digitorum longus
  
  
  
  • Origin:
    
    
    1. lateral condyle of the tibia
    2. upper anterior surface of fibula
    3. interosseous membrane
    4. crural fascia
  • Insertion:
    
    
    • dorsal surface of the bases of the middle & distal phalanxes of the 2nd-5th rays
    • (via 4 tendons and giving a fibrous expansion)
  • Action:
    
    
    1. extends the lateral 4 toes
    2. weak dorsiflexor & everts foot
  • Blood: anterior tibial artery
  • Nerve: deep peroneal nerve, L4,5,S1
  Peroneus tertius
  
  
  
  • Origin:
    
    
    1. distal 1/3 of anterior fibula
    2. distal & lateral aspect of extensor digitorum
  • Insertion: dorsal surface of base of 5th metatarsal
  • Action:
    
    
    1. extends the 5th toe
    2. weak dorsiflexor & everts foot
  • Blood: anterior tibial artery
  • Nerve: deep peroneal nerve, L4,5,S1
  
  
  
  

  Foot Musculature

  
  
  
   
  Abductor hallucis
  
  
  
  • Origin:
    
    
    1. medial process of calcaneal tuberosity
    2. flexor retinaculum
    3. plantar aponeurosis
    4. medial intermuscular septum
  • Insertion: medial aspect of base of proximal phalanx of hallux
  • Action:
    
    
    1. flexes the big toe (primary action)
    2. may assist in abduction of big toe
  • Blood: medial plantar artery
  • Nerve: medial plantar nerve, L5,S1
  Flexor digitorum brevis
  
  
  
  • Origin:
    
    
    1. medial process of calcaneal tuberosity
    2. plantar aponeurosis
  • Insertion:
    
    
    • both sides of the bases of the middle phalanx of rays 2-5
    • (each of the 4 tendons splits forming tunnel for FDL)
  • Action: flexes toes 2-5
  • Blood: medial plantar artery
  • Nerve: medial plantar nerve, L5,S1
  Abductor digiti minimi
  
  
  
  • Origin:
    
    
    1. lateral & medial processes of the calcaneal tuberosity
    2. plantar aponeurosis
    3. lateral intermuscular septum
  • Insertion: lateral aspect of base of proximal phalanx of 5th ray
  • Action:
    
    
    1. abducts 5th toe
    2. aids in flexing
  • Blood: lateral plantar artery
  • Nerve: lateral plantar nerve, S1,2
  Abductor ossis metatarsi quinti
  
  
  
  • Origin: from fibers of abductor digiti minimi
  • Insertion: into the 5th metatarsal
  • Action: abducts the 5th ray
  • Blood: lateral plantar artery
  • Nerve: lateral plantar nerve, S1,2
  Quadratus plantae
  
  
  
  • Origin:
    
    
    1. medial head: medial calcaneus
    2. lateral head: lateral calcaneus & long plantar ligament
  • Insertion:
    
    
    • lateral margin of tendon of flexor digitorum longus (FDL)
    • may send slips into the distal tendons
  • Action:
    
    
    1. assists FDL in flexing the distal phalanxes of 2nd-5th toes
    2. corrects FDL from pulling toes medially
  • Blood: lateral plantar artery
  • Nerve: lateral plantar nerve, S1,2
  Lumbricals
  
  
  
  • Origin: from tendons of FDL:
    
    
    1. 1st: medial aspect of tendon to 2nd ray
    2. 2nd-4th: two heads between the tendons in which they lie
  • Insertion: extensor tendons of EDL on dorsal foot
  • Action:
    
    
    1. flex proximal phalanges at MTP
    2. extend middle & distal phalanges at IP
  • Blood:
    
    
    1. 1st: medial plantar artery
    2. 2nd-4th: lateral plantar artery
  • Nerve:
    
    
    1. 1st: medial plantar nerve, L5,S1
    2. 2nd-4th: lateral plantar nerve, S1,2
  Flexor hallucis brevis
  
  
  
  • Origin:
    
    
    1. medial aspect of the cuboid
    2. lateral cuneiform
  • Insertion:
    
    
    1. medial aspect of base of proximal phalanx of hallux
    2. lateral aspect of base of proximal phalanx of hallux
  • Action: flexes hallux at MTP
  • Blood: medial plantar artery
  • Nerve: medial plantar nerve, L5,S1
  Adductor hallucis
  
  
  
  • Origin:
    
    
    1. oblique head: base of 2nd-4th metatarsals & long plantar ligament
    2. transverse head: deep transverse metatarsal ligament & plantar ligaments at MTP joints
  • Insertion: lateral aspect of base of proximal phalanx of hallux
  • Action:
    
    
    1. adduction of hallux at MTP
    2. flexes hallux at MTP
  • Blood: lateral plantar artery
  • Nerve: lateral plantar nerve, S1,2
  Flexor digiti minimi brevis
  
  
  
  • Origin:
    
    
    1. base of 5th metatarsal
    2. digital sheath of peroneus longus
  • Insertion: lateral aspect of base of proximal phalanx of 5th ray
  • Action: flexes the 5th toe at MTP
  • Blood: lateral plantar artery
  • Nerve: lateral plantar nerve, S1,2
  Plantar interossei (3 muscles)
  
  
  
  • Origin: medial aspect of 3rd-5th metatarsals (each muscle has a single head)
  • Insertion: medial aspect of base of proximal phalanx of the same ray (of 3rd-5th rays)
  • Action:
    
    
    1. adduct toes 3-5
    2. flex toes 3-5 at MTP
  • Blood: lateral plantar arch
  • Nerve: lateral plantar nerve (deep branch), S1,2
  Dorsal interossei (4 muscles)
  
  
  
  • Origin: from both metatarsals between which they lie
  • Insertion: base of proximal phalanx closest to the axis of the foot (2nd ray)
  • Action:
    
    
    1. abduct toes 2-4
    2. flexes toes 2-4 at MTP
  • Blood: lateral plantar arch
  • Nerve: lateral plantar nerve (deep branch), S1,2
  Extensor hallucis brevis
  
  
  
  • Origin:
    
    
    1. upper anterolateral calcaneus
    2. inferior extensor retinaculum
  • Insertion: base of proximal phalanx of hallux
  • Action: extends hallux
  • Blood: dorsalis pedis artery
  • Nerve: deep peroneal nerve, L4,5
  Extensor digitorum brevis
  
  
  
  • Origin:
    
    
    1. upper anterolateral calcaneus
    2. inferior extensor retinaculum
  • Insertion: middle & distal phalanges of 2nd-4th rays (via EDL)
  • Action: extends 2nd-4th rays
  • Blood: dorsalis pedis artery
  • Nerve: deep peroneal nerve, L4,5
  
  
  
  
  
  

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