lab practical terms to study

Deltoid

Origin: lateral 1/3 clavicle, acromion, spine of scapula. Insertion: deltoid tuberosity of humerus. Innervation: axillary nerve (C5–C6). Actions: abducts arm (middle), flexes/medially rotates (anterior), extends/laterally rotates (posterior).

Latissimus dorsi

Origin: spinous processes T7–L5, thoracolumbar fascia, iliac crest, ribs 9–12. Insertion: intertubercular sulcus of humerus. Innervation: thoracodorsal nerve (C6–C8). Actions: extends, adducts, medially rotates arm.

Trapezius

Origin: occipital protuberance, nuchal ligament, spinous processes C7–T12. Insertion: lateral clavicle, acromion, spine of scapula. Innervation: spinal accessory nerve (CN XI). Actions: elevates, retracts, depresses, upwardly rotates scapula.

Biceps brachii

Origin: long head—supraglenoid tubercle; short head—coracoid process. Insertion: radial tuberosity, bicipital aponeurosis. Innervation: musculocutaneous nerve (C5–C6). Actions: flexes elbow, supinates forearm, weak shoulder flexion.

Pectoralis major

Origin: clavicle, sternum, costal cartilages 1–6. Insertion: lateral lip of intertubercular sulcus. Innervation: medial & lateral pectoral nerves (C5–T1). Actions: adducts & medially rotates arm; flexes arm (clavicular head); extends from flexed (sternal head).

Triceps brachii

Origin: long head—infraglenoid tubercle; lateral head—posterior humerus; medial head—posterior humerus. Insertion: olecranon of ulna. Innervation: radial nerve (C6–C8). Actions: extends elbow; long head extends/adducts arm.

Adductor magnus

Origin: inferior pubic ramus (adductor part), ischial tuberosity (hamstring part). Insertion: linea aspera & adductor tubercle. Innervation: obturator nerve (adductor) & tibial division sciatic (hamstring). Actions: adducts thigh; flexes thigh (adductor); extends thigh (hamstring).

Biceps femoris

Origin: long head—ischial tuberosity; short head—linea aspera. Insertion: head of fibula. Innervation: tibial division (long), common fibular division (short). Actions: flexes knee; extends thigh (long head); laterally rotates flexed leg.

Gastrocnemius

Origin: medial & lateral condyles of femur. Insertion: calcaneus via Achilles tendon. Innervation: tibial nerve (S1–S2). Actions: plantarflexes ankle, flexes knee.

Gluteus maximus

Origin: ilium, sacrum, coccyx, sacrotuberous ligament. Insertion: IT band, gluteal tuberosity. Innervation: inferior gluteal nerve (L5–S2). Actions: extends & laterally rotates thigh; assists rising from sitting.

Sartorius

Origin: ASIS. Insertion: medial proximal tibia (pes anserine). Innervation: femoral nerve (L2–L3). Actions: flexes, abducts, laterally rotates thigh; flexes knee.

Gracilis

Origin: inferior pubic ramus. Insertion: medial proximal tibia (pes anserine). Innervation: obturator nerve (L2–L3). Actions: adducts thigh; flexes knee; medially rotates leg.

Tibialis anterior

Origin: lateral condyle & surface of tibia. Insertion: medial cuneiform, base of 1st metatarsal. Innervation: deep fibular nerve (L4–L5). Actions: dorsiflexes ankle, inverts foot.

Rectus femoris

Origin: AIIS & acetabular rim. Insertion: tibial tuberosity via patellar ligament. Innervation: femoral nerve (L2–L4). Actions: extends knee, flexes thigh.