Cranium
The cranium is the portion of the skull that encloses the brain. It is formed by several fused bones: frontal, parietal, temporal, occipital, sphenoid, and ethmoid. The frontal bone is broad and forms the forehead. The orbits are complete bony rings. The zygomatic arches extend laterally. Relative to the large facial skeleton (needed for the long jaws and large nasal passages), the cranial cavity itself is modest in size. The bones are palpable in many areas. Trauma can cause fractures, especially of the frontal or temporal bones. Sinusitis or dental disease can secondarily affect adjacent cranial bones. Advanced imaging (CT, MRI) is increasingly used for complex head trauma or neurologic cases.
Assess for asymmetry, swelling, crepitus, or nasal discharge after trauma. Radiography remains useful; CT is superior for complex fractures or sinus involvement. Brain injury may accompany skull fractures.
## Overview Skull fractures result from falls, kicks, or trailer accidents. Frontal fractures cause facial swelling and nosebleeds. Basilar fractures involving the temporal or occipital bones often d
## Overview Paranasal sinus disease includes infection (sinusitis), cysts, and dental-related problems affecting the frontal and maxillary sinuses. The most common sign is unilateral malodorous nasal
## Overview Mandibular fractures are breaks of the lower jaw, most often in the rostral (incisor) region. They result from kicks, falls, or the horse catching the jaw on an object. Signs include swel
Progressive proliferative osteoarthropathy of the temporohyoid joint that may cause fusion of the joint and fracture of the petrous temporal bone, damaging CN VII and CN VIII as they traverse the bone
## Overview Poll evil is inflammation or infection of the atlantal (cranial nuchal) bursa at the poll. It causes painful swelling, reluctance to flex the neck, and in chronic cases draining tracts. I
## Overview Temporomandibular joint (TMJ) dysfunction is inflammation or misalignment of the jaw joint. It causes reluctance to chew, quidding, head tossing, resistance to the bit, tenderness over th
Any head trauma with altered mentation, bleeding from ears or nose, or asymmetry of the skull needs immediate veterinary attention. Even if the horse seems bright, imaging is often warranted.
## Overview Skull fractures result from falls, kicks, or trailer accidents. Frontal fractures cause facial swelling and nosebleeds. Basilar fractures involving the temporal or occipital bones often damage the brain and are frequently fatal. Signs include bleeding from the ears or nostrils, head tilt, nystagmus, depression, and sometimes crepitus or a visible depression. ## Causes High-energy head trauma. ## Diagnosis Neurologic examination and radiographs or computed tomography. ## Treatment Supportive care for brain injury. Surgical repair for selected facial fractures. Basilar fractures with severe neurologic signs have a poor prognosis. ## Recovery and Prognosis Variable for facial fractures. Poor for basilar fractures with brain involvement. ## Prevention Safe handling and transport. Signs include: bleeding from ears or nostrils; neurologic signs (head tilt, nystagmus, depression); facial swelling; crepitus; epistaxis
## Overview Paranasal sinus disease includes infection (sinusitis), cysts, and dental-related problems affecting the frontal and maxillary sinuses. The most common sign is unilateral malodorous nasal discharge. Facial swelling, dull percussion, and head shaking may occur. Dental disease of the upper cheek teeth is a frequent underlying cause. ## Causes Primary bacterial infection, tooth-root abscess, sinus cyst, or neoplasia. ## Diagnosis Endoscopy, radiographs or computed tomography, and oral examination. ## Treatment Depends on the cause: antibiotics and lavage for primary sinusitis, tooth extraction for dental disease, or surgical removal for cysts. ## Recovery and Prognosis Good for primary sinusitis and most cysts. Dental-related cases require removal of the affected tooth. ## Prevention Regular dental care. Signs include: unilateral malodorous nasal discharge; facial swelling; dull percussion over the sinus; head shaking; possible dental pain
## Overview Mandibular fractures are breaks of the lower jaw, most often in the rostral (incisor) region. They result from kicks, falls, or the horse catching the jaw on an object. Signs include swelling, inability to close the mouth normally, malocclusion, drooling, and pain. Some fractures are open into the mouth. ## Causes Direct trauma. Young horses playing with objects and then being startled are commonly affected. Dental extraction complications can also occur. ## Diagnosis Oral examination and radiographs of the mandible. ## Treatment Many rostral fractures are stabilized with wire fixation between the teeth or conservative management if stable. More caudal fractures may need plates or pins. Antibiotics and soft feed are standard. ## Recovery and Prognosis Good for most rostral fractures. Fractures involving the angle of the mandible or temporomandibular joint have a more guarded outlook. ## Prevention Safe environments and supervision of young horses around objects they might grab. Signs include: swelling of the lower jaw; inability to close the mouth properly; malocclusion; drooling; pain on palpation; possible open fracture into the mouth
Progressive proliferative osteoarthropathy of the temporohyoid joint that may cause fusion of the joint and fracture of the petrous temporal bone, damaging CN VII and CN VIII as they traverse the bone. Signs include: Consult veterinarian for specific symptoms.; Head shaking; difficulty eating; ear rubbing; acute onset vestibular signs (head tilt, nystagmus, circling); facial nerve paralysis; keratitis (corneal ulceration from inability to blink)
## Overview Poll evil is inflammation or infection of the atlantal (cranial nuchal) bursa at the poll. It causes painful swelling, reluctance to flex the neck, and in chronic cases draining tracts. Infectious agents or trauma can be responsible. Treatment often requires surgical debridement and prolonged antibiotics. ## Causes Trauma or bacterial infection of the bursa. ## Diagnosis Clinical signs and ultrasound or surgical exploration with culture. ## Treatment Surgical drainage and debridement plus long-term antibiotics for infected cases. ## Recovery and Prognosis Guarded. Recovery is often prolonged. ## Prevention Avoidance of poll trauma. Signs include: painful swelling at the poll; reluctance to flex the neck; draining tract in chronic cases
## Overview Temporomandibular joint (TMJ) dysfunction is inflammation or misalignment of the jaw joint. It causes reluctance to chew, quidding, head tossing, resistance to the bit, tenderness over the temporal fossa, and visible muscle wasting above the eye. Dental problems or poor bitting often contribute. ## Causes Dental disease, trauma, or bit-related pressure. ## Diagnosis Palpation, dental examination, and sometimes radiographs or computed tomography of the TMJ. ## Treatment Correct dental issues, adjust bitting, anti-inflammatories, and physiotherapy. Injections are used in some cases. ## Recovery and Prognosis Good when the underlying cause is addressed. ## Prevention Regular dental care and appropriate bit fit. Signs include: reluctance to chew; quidding; head tossing; resistance to the bit; tenderness over the temporal fossa; muscle wasting above the eye
Assess for asymmetry, swelling, crepitus, or nasal discharge after trauma. Radiography remains useful; CT is superior for complex fractures or sinus involvement. Brain injury may accompany skull fractures.
Any head trauma with altered mentation, bleeding from ears or nose, or asymmetry of the skull needs immediate veterinary attention. Even if the horse seems bright, imaging is often warranted.
See the Cranium on our interactive 3D horse model. Open 3D Model