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Intrinsic Muscles of Hand/ 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.

Thenar Muscles of Hand
Opponents policies
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Function: Opposition of the thumb
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Origin: Flexor retinaculum and tubercle of trapezium
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Insertion: Lateral aspect of the first metacarpal
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Innervation: Recurrent branch of the median nerve (C8, T1)
Abductor policies Brevis
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Function: Abduction of the thumb at the metacarpophalangeal joint
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Origin: Flexor retinaculum and tubercle of the scaphoid
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Insertion: Lateral aspect of proximal phalanx of the first finger
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Innervation: Recurrent branch of the median nerve (C8, T1)
Flexor policies Brevis
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Function: Flexion of the thumb at the metacarpophalangeal joint
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Origin: Flexor retinaculum and tubercle of trapezium
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Insertion: Lateral aspect of proximal phalanx of the first finger
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Innervation: Recurrent branch of the median nerve (C8, T1)
Adductor Compartment
Adductor pollicus
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Function: Adduction of the thumb
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Origin: Second, third metacarpal, and capitate
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Insertion: Proximal phalanx and extensor expansion of 1st finger
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Innervation: Deep branch of ulnar nerve (C8, T1)
Hypothenar Muscles
Abductor digiti minimi
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Function: Abduction of the little finger at the metacarpophalangeal joint
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Origin: Pisiform
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Insertion: Medial aspect of proximal phalanx of fifth finger
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Innervation: Deep branch of ulnar nerve (C8, T1)
Flexor digiti minimi brevis
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Function: Flexion of the little finger at the metacarpophalangeal joint
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Origin: Flexor retinaculum and hook of hamate
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Insertion: Medial aspect of proximal phalanx of fifth finger
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Innervation: Deep branch of ulnar nerve (C8, T1)
Opponens digiti minimi
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Function: Opposition of the little finger
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Origin: Flexor retinaculum and hook of hamate
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Insertion: Medial aspect of fifth metacarpal
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Innervation: Deep branch of ulnar nerve (C8, T1)
Short Muscles
Lubricants
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Function: Flexion of the metacarpophalangeal joints with extension of the interphalangeal joints
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Origin: Arise from tendons of flexor digitorum profundus. First 2 are unipennate, and the third and fourth are bipennate
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Insertion: Extensor expansions of second, third, fourth, and fifth finger
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Innervation: Median nerve (C8, T1) for the lateral 2 lumbricals, deep branch of ulnar nerve (C8, T1) for the medial 2 lumbricals
Dorsal interossei
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Function: Abduction of the second, third, and fourth finger away from the axial line
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Origin: Adjacent metacarpals
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Insertion: Extensor expansions and proximal phalanges of the second, third, and fourth fingers
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Innervation: Deep branch of ulnar nerve (C8, T1)
Palmar interossei
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Function: Adduction of the second, third, and fourth finger towards the axial line
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Origin: Palmar surfaces of second, fourth, and fifth metacarpals
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Insertion: Extensor expansions and proximal phalanges of the second, fourth, and fifth fingers
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Innervation: Deep branch of ulnar nerve (C8, T1)
Surgical Considerations
The deltoid is a significant factor when considering the anterior surgical approach to gain access to the shoulder joint. Some of these technical procedures include, but are not limited to the following:
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Open Bankart repair/capsular reconstructions – indicated in the setting of recurrent anterior (or other directional) instability of the shoulder
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Shoulder arthroplasty – indicated for cases of post-traumatic deformity, advanced degenerative pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।" data-rx-term="arthritis" data-rx-definition="Arthritis means joint inflammation causing pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।">arthritis, and/or avascular necrosis includes hemiarthroplasty, total shoulder arthroplasty (TSA), reverse total shoulder arthroplasty (TSA)
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Rotator cuff repair contemporary – indications remain somewhat controversial although most of these procedures are now being performed arthroscopically popular approaches (as opposed to the deltopectoral approach) include the mini-open approach (lateral deltoid-splitting approach)
References
- https://www.ncbi.nlm.nih.gov/books/NBK507892/
- https://www.ncbi.nlm.nih.gov/books/NBK525990/
- https://www.ncbi.nlm.nih.gov/books/NBK537258/
- https://www.ncbi.nlm.nih.gov/books/NBK499858/
- https://www.ncbi.nlm.nih.gov/books/NBK545221/
- https://www.ncbi.nlm.nih.gov/books/NBK537056/
- https://www.ncbi.nlm.nih.gov/books/NBK482410/
- https://teachmeanatomy.info/upper-limb/bones/clavicle/
- https://www.kenhub.com/en/library/anatomy/the-clavicle
