What are the 9 componets of the extensor hood mechanism and what do they do?
Extensor digitorum tendon - inserts into the base of the proximal phalanxs.
dorsal hood - is composed of two sets of fibers that run around the MCP joint.
Transverse fibers - wrap around the MCP joint and attach to the palamr plate - they act as a sling and aide in extension at the MCP joint.
Oblique fibers - run distally and merge into the central tendon and lateral bands - they serve as an attachment site for the lumbricals and interossei. They also tranfer the force of the hands intrinsic muscles to the lateral band and central tendon.
central tendon -is continuation of the central band of the ED tendon and it transmits force fro the ED , interosseo and limbrical to the middle phalanx were it inserts.
lateral bands - comes of the central tendon at the middle of the proximal phalanx and it transmits force from the ED , interossei and lumbricals to the distal phalanx.
terminal tendon - the merging of the two lateral bands which insert onto the base of the distal phalanx.
oblique retinacular ligament - runs from the flexor sheath to the lateral bands - and helps to coordinate the movement of the PIP and DIP joints of the fingers.
intrinsic hand muscles - the lumbricals dorsal and palamr interossei - extend the PIP and DIP joints.