Anatomy

Important Muscles origin, insertion, innervation & action for exams

 Origin, Insertion, Innervation and Action of commonly asked muscles of our body.

Abductor magnus [Hamstring part]

Origin: Ischial tuberosity

Insertion: adductor tubercle of femur

Innervation: tibial part of sciataic nerve (L4)

Action: extends thigh

Abductor magnus[Adductor part]

Origin: Adductor part: Inferior ramus of pubis and ramus of ischium

Insertion: Gluteal tuberosity, linea alba, medial supracondylar line

Innervation: Obturator nerve (L2, 3, 4)

Action: Flexes thigh

Biceps brachii

Origin: Short head: tip of coracoid process of scapula.

Longhead: Supraglenoid tubercle of scapula

 

Insertion: Tuberosity of radius and fadcia of forearm via bicipital aponeurosis.

 

Innervation: Musculocutaneous(C5,C6)

Brachialis

Origin: Distal half ant surface of humerous.

Insertion: Coronoid process & tuberosity of ulna

Innervation: Musculocutaneous nerve (C5 , C6)

Action: Flexes forearm in all positions.

Brachioradialis

Origin: Proximal 2/3 lateral supracondylar ridge of humerous.

Insertion: Lateral surface of distal end of radius.

Innervation: Radial nerve (C6, C7)

Action: Flexes forearm

Deltoid

Origin: Lateral third of clavicle, acromian and spine of scapula.

Insertion: Deltoid tuberosity of humerous

Innervation: Axillary nerve (C5, C6).

Action: Anterior part: Flexes & medially rotates arm.

Middle part: abducts arm

Posterior part: extends & laterally rotates arm.

Digastric

Origin: Anterior belly: Digastric fossa of mandible

Posterior belly: Mastoid notch of temporal bone

Insertion: Intermediate tendon to body and greater horn of hyoid bone.

Action: Depresses mandible, raises hyoid bone & steadies it during swallowing and speaking

External oblique

Origin: External surface of 5th-12th ribs

Insertion: linea alba, pubic tubercle, ant half of iliac crest

Innervation: Thoracoabdominal nerve

Action: Flexes & rotates trunk and support abdominal viscera.

Flexor carpa radialis

Origin: Medial epicondyle of humerous

Insertion: Base of 2nd and 3rd metacarpal

Innervation: Median nerve

Action: Flexion and abduction at wrist joint

Flexor carpa ulnaris

Origin: Humeral head: Medial epicondyle of humerous, coronoid process of ulna

Radial head: Olecranan process & posterior border of unla

Insertion: Pisiform, back of hamate, base of 5th metacarpal

Innervation: Ulnar nerve

Action: Flexion and adduction at wrist joint

Flexor digitorum profundus

Origin: Upper 3/4th of ant & medial surface of unla

                Upper 3/4th of post border of ulna

                Olecranan and coronoid process of ulna

                Adjoining interosseous membrane

Insertion: Base of distal phalanx of medial 4 digits

Innervation: Medial half: ulnar nerve; Lateral half: ant interosseous neve (C8, T1)

Action: Flexion of distal phalanx, assist flexion of other interphalangeal joints & wrist joint.

Flexor dorsum superficialis

Origin: Homeroulnar head: Medial epicondyle of humerous, coronoid process of ulna

Radial head: Anterior oblique line of radius

Insertion: Sides of middle phalanx of 2nd to 5th digits

Innervation: Median nerve

Action: Flexion of middle phalanx, assist in flexing proximal phalanx and wrist joint

Flexor pollicis longus

Origin: Upper 3/4th of ant surface of radius.

Lower 1/4th of the ant surface of ulna

Adjoining interosseous membrane

Insertion: Lower ¼ of ant surface of radius.

Innervation: Ant interosseous membrane

Action: Position of forearm.

Gastrocnemius

Origin:  Lateral head: Lateral aspect of lateral condyle of femur.

Medial head: Popliteal surface of femur, superior to medial condyle

Insertion: Posterior surface of calcaneus via calcaneal tendon

Innervation: Tibial nerve (S1, 2)

Action: Planter flexes ankle when knee is extended and flexes leg at knee join

Gluteus maxiums

Origin: Ilium, posterior to posterior gluteal line; dorsal surface of sacrum & coccyx; and sacrotuberous ligament.

Insertion: Most fibers end in iliotibial tract that inserts into lateral condyle of Tibia. Some fibers insert into gluteal tuberosity of femur.

Innervation: Inferior gluteal nerve.(L5, S1 & S2)

Action: Extends thigh ( esp from flexed position) and assist in its lateral rotation.

Gluteus medius

Origin: Ext surface of ilium between ant and post gluteal line.

Insertion: Lateral Surface of greater trochanter of femur.

Innervation: Superior gluteal nerve (L5 & S1)

Action: Abducts & medially rotates thigh, keeps pelvis level when opposite tag is raised.

Latissimus dorsi

Origin: spinous process of inferior 6 thoracic vertebrae, thoracolumbar fascia, illiac crest and inferior 3 or 4 ribs.

Insertion: floor of intertubercular groove of humerous

Innervation: Thoracodorsal nerve (C6, C7, C8)

Action: Extends, abducts and medially rotates humerous. Raises body towards arm during climbing.

Palmaris longus

Origin: Medial epicondyle of humerous

Insertion: Flexor retinaculum and palmar aponeurosis

Innervation: Median nerve

Action: Flexion at wrist joint

Pectoralis major

Origin: Clavicular head: Ant surface of medial half of clavicle.

                Sternocostal head: ant surface of sternum, superior six costal cartilages and aponeurosis of external oblique muscles

Insertion: Lat lip of inter tubercular groove of humerous

Innervation: Lateral and medial pectoral nerves:

Action: Adducts and medially rotates humerous. Clavicular head: flexes humerous. Sternocostal head: extends humerous from flexed position

Popliteus

Origin: Lateral surface of lateral condyle of femur

Insertion: Post surface of tibia, superior to soleal line

Innervation: Tibial nerve (L4, 5 & S1)

Action: Weakly flexes knee and unlocks it.

Pronator teres

Origin: Medial epicondyle of humerous & coronoid process of ulna.

Insertion: Middle of lateral surface of radius

Innervation: Medial (C6, C7) nerve

Action: Pronates and flexes forearm (at elbow)

Psoas major

Origin: Sides of T12-L5 vertebrae and discs in betn them; transverse process of all lumbar vertebrae.

Insertion: Lesser trochanter of femur

Innervation: Ventral rami of lumbar nerves (L1, L2 & L3) 

Action: Act conjointly in flexing thigh at hip joint & stabilizing this joint.

Quadratus Lumborus

Origin: Transverse process of L5; iliolumbar ligament; inner lip of the iliac crest

Insertion: Transverse process of upper 4 lumbar vertebrae; medial half of lower border of last (12th) rib.

Innervation: Ventral rami of spinal nerves (T12 – T14)

Action: Fixes last rib during inspiration; extend lumbar vertebral column.

Rectus abdominalis

Origin: Pubic symphysis and pubic crest

Insertion: Xiphoid process & 5-7th costal cartilage

Innervation: Thoracoabdominal nerve

Action: Flexes trunk and compresses abdominal viscera.

Rectus femoris

Origin: Ant inf iliac spine & ilium sup to acetabulum

Insertion: base of patella by patellar ligament to tibial tuberosity.

Innervation: Femoral (L2, 3, 4)

Action: Extend leg at knee joint steadies’ hip joint & helps ilipsoas to flex thigh

Sartorious

Origin: Ant sup iliac spine & sup part of notch inf to it

Insertion: Sup part of medial surface of tibia

Innervation: Femoral (L2,3)

Action: Flexes, abducts and laterally rotates thigh at hip joint flexes leg at knee joint.

Serratus Anterior

Origin: 8 digitations from upper 8 ribs; fascia covering intervening intercostal muscles

Insertion: Costal surface of scapula along its medial border.

Innervation:  Long thoracic (C5, C6, C7)

Action: Pushing and punching movement; holds and rotates the scapula.

Soleus

Origin: Post aspect of head of fibula, sup fourth of post surface of fibula, and medial border of tibia. This forms soleal arch.

Insertion: Posterior surface of calcaneus via calcaneal tendon

Innervation: Tibial nerve (S1, 2)

Action: Planterflexes ankle independent of position of knee

Sternocledomastoid

Origin: Sternal head: ant surface of manubrium sternum.

                Clavicular head: Sup surface of the medical third of clavicle.

 

Insertion: Lat surface of mastoid process of temporal bone & lateral half of sup nuchal line.

 

Innervation: Spinal root of accessory nerve(motor) and C2,C3 nerves for pain and proprioception.

 

Action: The head to one side i.e. laterally ; flexes neck & rotates it so face is turned sup towards opposite side acting together, the two muscle flex neck so chin is thrust forward.

Temporalis

Origin: Floor of temporal fossa and deep surface of temporal fascia.

 

Insertion: Tip and medial surface of coronoid process & ant border of ramus of mandible.

 

Innervation: Deep temporal branch of mandibular nerve.

 

Action: Elevates mandible closing jaws, its posterior fibers retrude mandible after protrusion.

Tensor of fascia lata

Origin: Ant sup iliac spine and ant part of iliac crest

Insertion: iliotibial tract that attaches to lateral condyle of tibia

Action: Abducts, medially rotates, flexes thigh helps to keep knee extended ; steadies trunk on thigh

Tibialis posterior

Origin: Interosseous membrane, posterior surface of tibia inf to soleal line & posterior surface of fibula

Insertion: Tuberosity of navicular, cuneiform and cuboid and base of 2nd, 3rd and 4th metatarsals

Innervation: Tibial nerve (L4, 5)

Action: Planter flexes ankle and inverts foot

Triceps brachii

Origin: Long head: Infraglenoid tubercle of scapula.

Lateral head: ridge above radial groove in posterior surface of humerous.

Medial head: area below the radial groove in posterior surface of humerous

Insertion: Proximal end of olecranon process of Ulna and fascia of forearm

Innervation: Radial nerve (C6, C7, C8)

Action: Chief extensor of elbow joint.

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