EXTENSOR EXPANSION Flashcards
Aka “extensor hood”
Extensor Expansion
The extensor expansion covers the _____?
MTPJ and extends to the PIPJ
what are the two parts of the extensor expansion?
extensor sling
extensor wing
name this part of the extensor expansion?
Proximal part
Fibers are oriented transversely
Fibers pass around the MTPJ and attach to the DTML
extensor sling
name this part of the extensor expansion?
distal part
Fibers are oriented obliquely
extensor wing
what are the encased tendons of the extensor expansion?
Extensor Digitorum Longus Tendon
Extensor Digitorum Brevis Tendon
Plantar Interossei Tendons (PADs)
Dorsal Interossei Tendons (DABs)
Lumbrical Muscles
name this tendon of the extensor expansion?
○ Passes into the Extensor Expansion dorsally
○ Exits the wing at the head of the proximal phalanx, which is where it divides into 3 slips
■ Central slip inserts on base of middle phalanx
■ 2 lateral slips merge distally and insert on the base of the distal phalanx
Extensor Digitorum Longus Tendon
name this tendon of the extensor expansion?
Passes into the extensor sling lateral to EDL tendon, and then inserts on the lateral aspect of the EDL tendon
Extensor Digitorum Brevis Tendon
name this tendon of the extensor expansion?
○ Passes deep to the medial aspect of the sling
○ Insert on the medial aspect of the bases of the proximal phalanges 3-5
Plantar Interossei Tendons (PADs)
name this tendon of the extensor expansion?
○ 1st DAB passes within the medial aspect of the sling and then inserts on the medial aspect of 2nd proximal phalanx
○ DABs 2-4 pass within the lateral aspect of the sling and insert on lateral aspect of proximal phalanges 2-4, respectively
Dorsal Interossei Tendons (DABs)
name this tendon of the extensor expansion?
○ Pass from origin (FDL tendon) to insertion (extensor wing)
○ Tendon passes plantar to the DTML
Lumbrical Muscles
