Anatomy and Topography
The mandible (mandibula) is an unpaired, horseshoe-shaped movable bone consisting of a body (corpus mandibulae) and paired rami (ramus mandibulae). The ramus terminates superiorly in two processes:
- Coronoid process (processus coronoideus) — the anterior, pointed process.
- Condylar process (processus condylaris) — the process of the ramus bearing the head and neck.
- Mandibular notch (incisura mandibulae) — a depression separating the coronoid and condylar processes.
- Temporal crest (crista temporalis) — a bony ridge into which the coronoid process smoothly transitions anteriorly and inferiorly.
The border of the mandibular ramus forms the posterior boundary of the facial region. On the medial surface of the ramus, below the notch, lies the mandibular foramen (foramen mandibulae), which marks the beginning of the mandibular canal.
Muscle Attachments
The pattern of mandibular fractures and bone fragment displacement is largely determined by the pull of the masticatory muscles attached to it.
- Temporalis muscle (m. temporalis) — attaches to the coronoid process.
- Origin and course: The muscle originates from the periosteum of the temporal fossa (planum temporale) and the deep surface of the temporal fascia. Its fibers converge inferiorly and anteriorly.
- Insertion: The fibers transition into a powerful tendon that attaches not only to the coronoid process itself but extends along the anterior border of the mandibular ramus.
Clinical and Surgical Significance
The tendon of the temporalis muscle is attached to the coronoid process so firmly that during certain surgeries, the coronoid process must be surgically osteotomized rather than dissecting the tendon.
Anatomical Distinction: Coronoid Process of the Ulna
In osteology, there is another structure with an identical name — the coronoid process of the ulna (processus coronoideus ulnae).
- It is located on the proximal epiphysis of the long tubular ulna (ulna), which is situated on the medial side of the forearm.
- Together with the olecranon (olecranon), it forms the boundaries of the trochlear notch (incisura trochlearis).
- It serves as the attachment site for the brachialis muscle (m. brachialis), the primary flexor of the forearm. Some bundles of this muscle blend into the anterior wall of the elbow joint capsule, protecting it from impingement.
- On a sagittal section of the elbow joint, the coronoid fossa (fossa coronoidea) of the humerus is clearly visible.