The stylomandibular ligament is a specialized band of the cervical fascia

Cervical fascia

The cervical fascia is fascia found in the region of the neck.It mainly refers to the deep cervical fascia. However, there are other cervical fascia:*superficial cervical fascia*prevertebral fascia...

, which extends from near the apex of the styloid process

Styloid process

In anatomy, a styloid process , usually serving as points of attachment for muscles, refers to the slender, pointed process of :* temporal bone of the skull - Temporal styloid process...

 of the temporal bone

Temporal bone

The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebrum.The temporal bone supports that part of the face known as the temple.-Parts:The temporal bone consists of four parts:* Squama temporalis...

 to the angle and posterior border of the angle of the mandible

Angle of the mandible

At the junction of the lower border of the ramus of the mandible with the posterior border is the angle of the mandible, which may be either inverted or everted and is marked by rough, oblique ridges on each side, for the attachment of the Masseter laterally, and the Pterygoideus internus medially;...

, between the Masseter and Pterygoideus internus.

This ligament separates the parotid from the submandibular gland

Submandibular gland

The paired submandibular glands are salivary glands located beneath the floor of the mouth. In humans, they account for 70% of the salivary volume and weigh about 15 grams. Unstimulated in humans, the percentage contribution to whole saliva; ~25% Parotid, Submandibular and Sublingual ~ 67% and...

 and medial pterygoid, and from its deep surface some fibers of the Styloglossus

Styloglossus

The Styloglossus, the shortest and smallest of the three styloid muscles, arises from the anterior and lateral surfaces of the styloid process, near its apex, and from the stylomandibular ligament....

 take origin.

Although classed among the ligaments of the temporomandibular joint

Temporomandibular joint

The temporomandibular joint is the joint of the jaw and is frequently referred to as TMJ. There are two TMJs, one on either side, working in unison. The name is derived from the two bones which form the joint: the upper temporal bone which is part of the cranium , and the lower jaw bone called the...

, it can only be considered as accessory to it.

This ligament along with the sphenomandibular ligament is responsible for limitation of mandibular movements (limit excessive opening).