Hand Muscles Anatomy PDF

MUSCLES OF THE HAND MUSCLES OF THE HAND ❖ Muscles acting on the hand can be divided into two groups: extrinsic and intrinsic muscles. ❖ The extrinsic muscles are located in the anterior and posterior compartments of the forearm. They control crude movements and produce a forceful grip....

MUSCLES OF THE HAND MUSCLES OF THE HAND ❖ Muscles acting on the hand can be divided into two groups: extrinsic and intrinsic muscles. ❖ The extrinsic muscles are located in the anterior and posterior compartments of the forearm. They control crude movements and produce a forceful grip. ❖ The intrinsic muscles of the hand are located within the hand itself. They are responsible for the fine motor functions of the hand. ❑ These include the adductor pollicis, palmaris brevis, interossei, lumbricals, thenar and hypothenar muscles.  MUSCLES COMPARTMENT OF THE HAND ❖ The hand has four muscles compartments: 1. Thenar compartment - move the thumb (digit 1) e.g., Abductor pollicis brevis, Flexor pollicis brevis, Opponens pollicis brevis 2. Hypothenar compartment - move the pinky (digit 5) e.g., Abductor digiti minimi, Flexor digiti minimi, Opponens digiti minimi 3. Adductor compartment e.g., Adductor pollicis 4. Central compartment e.g., Dorsal interossei, Palmar interossei, lumbrical THENAR COMPARTMENT: IT MOVE THE THUMB (DIGIT 1) ABDUCTOR POLLICIS BREVIS, FLEXOR POLLICIS BREVIS, OPPENENS POLLICIS BREVIS. THENAR COMPARTMENT ❖ The thenar muscles are three short muscles located at the base of the thumb. ❖ The muscle bellies produce a bulge, known as the thenar eminence. ❖ They are responsible for the fine movements of the thumb. ❖ The median nerve innervates all the thenar muscles. ❖ These muscles are; Abductor pollicis brevis, Flexor pollicis brevis, Oppenens pollicis brevis. Abductor Pollicic Brevis ❖ Origin: from the tubercles of scaphoid and trapezium and adjacent flexor. ❖ Insertion: Attaches to lateral side of Proximal phalanx and extensor hood of thumb retinaculum ❖ Action: Abducts thumb at metacarpophalangeal joint. ❖ Innervation: Recurrent branch of median nerve. [C8,T1] Flexor Pollicis Brevis ❖ Origin: Tubercle of the trapezium and flexor retinaculum. ❖ Insertion: attaches to the base of the proximal phalanx of the thumb. ❖ Action: Flexes thumb at metacarpophalangeal joint. ❖ Innervation: Recurrent branch of median nerve[C8,T1]. Opponens Pollicis Brevis ❖ Origin: Tubercle of trapezium and flexor retinaculum ❖ Insertion: it inserts into the lateral margin of the metacarpal of the thumb (i.e. the first metacarpal). ❖ Action: Medially rotates thumb. ❖ Innervation: Recurrent branch of median n. [C8,T1] HYPOTHENAR COMPARTMENTS: IT MOVE THE PINKY (Digit 5) ABDUCTOR DIGITI MINIMI, FLEXOR DIGITI MINIMI, OPPONENS DIGITI MINIMI. HYPOTHENAR COMPARTMENTS ❖ The hypothenar muscles produce the hypothenar eminence – a muscular protrusion on the medial side of the palm, at the base of the little finger. ❖ These muscles are similar to the thenar muscles in both name and organisation. ❖ The ulnar nerve innervates the muscles of the hypothenar eminence. ❖ They are responsible for the fine movements of the PINKY (Digit 5) ❖ These muscles are: Abductor digiti minimi, Flexor digiti minimi, Opponens digiti minimi.  ABDUCTOR DIGITI MINIMI ❖ Origin: it originates from the Pisiform, the pisohamate ligament, and tendon of flexor carpi ulnaris ❖ Insertion: Proximal phalanx of little finger ❖ Action: Abducts little finger at metacarpophalangeal joint. ❖ Innervation: Deep branch of ulnar nerve [C8,T1 FLEXOR DIGITI MINIMI ❖ Origin: it originates from the hook of the hamate and flexor retinaculum ❖ Insertion: it insert proximal phalanx of little finger ❖ Action: Flexes little finger at metacarpophalangeal joint. ❖ Innervation: Deep branch of ulnar nerve. [C8,T1] OPPONENS DIGITI MINIMI ❖ Origin: it originate from Hook of hamate and flexor retinaculum ❖ Insertion: it insert on medial aspect of metacarpal V ❖ Action: Laterally rotates metacarpal V ❖ Innervation: Deep branch of ulnar nerve. [C8,T1 ADDUCTOR COMPARTMENT Adductor pollicis ADDUCTOR POLLICIS This is large triangular muscle with two heads. ❖ Origin: Transverse head: metacarpal 3; oblique head: capitate and bases of metacarpals 2 and 3. ❖ Insertion: it originate base of proximal phalanx and extensor hood of thumb ❖ Action: Adducts thumb ❖ Innervation: Deep branch of ulnar n. [C8,T1] CENTRAL COMPARTMENT ❖ The central compartment consist of the following muscles: Lumbrical Palmar interossei Dorsal interossei  LUMBRICALS ❖ These are four lumbricals in the hand, each associated with a finger. ❖ They are very crucial to finger movement, linking the extensor tendons to the flexor tendons. ❖ Denerveration of these muscles is the basis for the ulnar claw and hand of benediction. ❖ Origin: originates from the tendons of flexor digitorum profundus. ❖ Insertion: it insert on the extensor hoods of index, ring, middle, and little fingers ❖ Action: Flex metacarpophalangeal joints while extending interphalangeal joints ❖ Innervation: Medial two by the deep branch of the ulnar nerve.; lateral two by digital branches of the median nerve. INTEROSSEI ❖ The interossei muscles are located between the metacarpals. ❖ They can be divided into two groups: the dorsal and palmar interossei. ❖ In addition to their actions of abduction (dorsal interossei) and adduction (palmar interossei) of the fingers, the interossei also assist the lumbricals in flexion and MCP joints and extension at the IP joints. DORSAL INTEROSSEI ❖ Origin: it originates from adjacent sides of metacarpals (1,2,3 and 4) ❖ Insertion: Extensor hood and base of proximal phalanges of the index, middle, and ring fingers ❖ Action: Abduction of index, middle, and ring fingers at the metacarpophalangeal joints ❖ Innervation: Deep branch of ulnar nerve. [C8,T1] PALMAR INTEROSSEI ❖ Origin: Sides of metacarpals ❖ Insertion: it insert to the extensor hoods of the index, ring, and little fingers and the proximal phalanx of thumb. ❖ Action: Adduction of the index, ring, and little fingers at the metacarpophalangeal ❖ Innervation: Deep branch of ulnar nerve. [C8,T1]