Sphenomandibular ligament
Ligamentum sphenomandibulare
A thin flat band beside the jaw joint, running from the spine of the sphenoid down to the lingula of the mandible.
At a glance
- English
- Sphenomandibular ligament
- Latin (TA2)
- Ligamentum sphenomandibulare
- System
- Ligament
- Region
- Head
- Side
- Paired, left and right
About the sphenomandibular ligament
The sphenomandibular ligament is an accessory ligament of the temporomandibular joint that lies well away from the joint itself, on the inner side of the mandibular ramus. Its upper end is fixed to the spine of the sphenoid bone. It widens as it descends and attaches below to the lingula, the thin tongue of bone that overlaps the front of the mandibular foramen. It is pierced by the nerve and vessels to mylohyoid.
It is a remnant of the first pharyngeal arch: in the embryo the cartilage of this arch, Meckel's cartilage, extends back to the ear, and part of its sheath persists as this ligament. That origin explains why it runs from the skull to the jaw at some distance from the joint.
The ligament has a crowded neighbourhood. The auriculotemporal nerve and lateral pterygoid are lateral to it; near its upper end the chorda tympani is medial to it, and lower down the medial pterygoid lies medial and below. Between the ligament and the neck of the mandible runs the maxillary artery, and between the ligament and the ramus pass the inferior alveolar nerve and vessels together with a small lobe of the parotid gland.
Functionally it is slack when the jaw is closed and tightens as the condyle glides forwards beyond the line of the lateral ligament, so it helps to check excessive downward and forward movement of the mandible. It is a key landmark in dentistry: in an inferior alveolar nerve block, anaesthetic is placed in the space between the ligament and the ramus, close to the mandibular foramen. A needle placed on the wrong side of the ligament gives a failed block.
Attachments and function
- Attaches from
- The spine of the sphenoid bone.
- Attaches to
- The lingula of the mandible at the mandibular foramen.
- Function
- Becomes taut as the jaw opens widely and helps limit excessive downward and forward travel of the mandible.
Anthromica
See the sphenomandibular ligament where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
