Mystery-Neck Pony

Even a slightly misaligned hyoid apparatus (the group of bones in the neck that support the tongue and larynx) in a horse can have a wide-ranging impact on the function and movement of fascia and certain muscles, even affect the nervous system. This anatomical misalignment can potentially lead to several neuromuscular and mechanical problems.

The brachial plexus is a network of nerves that originate from the cervical spine (C5–T1) and controls movement and sensation in the forelimbs. If the hyoid apparatus causes muscular imbalances or tension in the scalenus, brachiocephalicus, or trapezius, it may lead to compression or irritation of the brachial plexux. Even a small misalignment in this area can create a chain of issues that affects posture, muscle coordination, and nerve function.

The cervical nerve roots are responsible for motor control and sensation in the neck and upper limbs. Any misalignment or compression of these nerve roots due to a rotated hyoid can lead to numbness or tingling sensations along the neck, shoulders, or forelimbs.

Every muscle in the horses body eventually connects to the hyoid.

The bones that make up the hyoid apparatus are the only bones in the body not to connect to another bone - they are held in place solely by ligaments.

The deep muscles of the neck that help attach the neck to the thoracic cavity (the chest region) are primarily responsible for stabilizing the cervical vertebrae, supporting the connection between the neck and the thoracic spine, and enabling the movement of the neck relative to the chest and shoulders. These muscles help in anchoring the neck to the thoracic region and assist in various neck functions like flexion, extension, and lateral movement.

Cranial Nerve XI (Accessory Nerve): innervates the trapezius, sternocleidomastoid, and other muscles in the neck and shoulders. Compression or irritation of the accessory nerve due to a rotated hyoid apparatus can reflect on surrounding deep muscles.

Cranial Nerve V (Trigeminal Nerve): Although the trigeminal nerve mainly serves the face, it can also be involved in referred pain if tension or misalignment in the hyoid apparatus causes discomfort or changes in the neck's posture. This may manifest as sensitivity around the face, jaw, or sinuses.

The hyoid apparatus consists of a selection of small bones that articulate together. Its name means "shaped like the letter upsilon (Y)", and it is situated at the base of the skull; between the cheeks of the horse. The hyoid apparatus connects to the skull via the temporohyoid joint. At this joint, the hyoid apparatus articulates with the skull. The hyoid apparatus gives biomechanical form and function to the larynx, pharynx and the tongue.

The facial nerve (Cranial Nerve VII) has several branches that innervate muscles around the face, including those involved in ear muscle control. While the facial nerve is responsible for motor function (movement) in the ear muscles, the sensation in the external ear is primarily mediated by Cranial Nerve V (the trigeminal nerve), particularly its ophthalmic and maxillary branches. These branches provide sensory innervation to the skin, mucosa, and structures around the ear.

A position of the fetus during gestation can influence the development of certain cranial nerves and associated structures. If a horse fetus is positioned in a way that causes compression or restriction of the facial nerve or the cranial nerve roots during the critical period of nerve development, it could lead to improper development or positioning that may or may not interfere with other factors later in life yet with properly timed care addressing arising symptoms helping the body into functional alignment the horse may learn to manage and use his features with little to simple routine maintenance therapies like accupuncture, craniosacral and similar.

horse repeatedly engages in seemingly involuntary lower jaw/teeth rotation or shifting to the right side and down when marked areas are palpated

The tongue connects to the hyoid apparatus.

The hyoid apparatus has muscular connections from the throat to the forelimbs (omothyroid), shoulder (omohyoid) and sternum (sternohyoid).

Sternohyoid = hyoid to sternum; Omohyoid = basihyoid to medial scapula/subscapular fascia; these muscles provide a direct connection from the hyoid apparatus to the shoulder of the horse via the ventral neck. Tension within these muscles, along with sternothyroid, results in restricted shoulder movement and the development of hypertonicity. Contraction of these muscles can put strain on the temporomandibular joint (TMJ). Additionally, hypertrophy and hypertonicity of the sternocephalic muscle can occur when the horse strains against the bit as a result of negative pressure upsetting the hyoid apparatus.

The muscle chain continues ventrally, connecting the pectoral area to the abdominal muscles.

The abdominal muscles are connected to the pelvic muscles.

The hyoid and cranial nerves are intricately connected with the jaw.

Small muscles of the hyoid apparatus connect to the TMJ and the poll. The TMJ has a dual purpose of mastication and registering of postural information. Therefore, it is an important anatomical location for nerves that control proprioception and balance; the highest concentration of mechanoreceptors (sensory nerves that report shape change) are found in the periphery of the disc and at the attachment site of local ligaments.The TMJ articulates with the hyoid apparatus.

Hypertonicity of the hyoid musculature = often have lateral imbalances of the hyoid bones. When viewing the horses head from underneath, the tongue can be located in the depression between the two ramus of the mandibles. Applying gentle pressure underneath can identify a bony structure, which is the basihyoid bone. Lumps around this area are likely saliva glands. Feeling the location of this bone can determine deviation of the hyoid. Sliding the tips of the fingers along the inside curvature of the mandible upwards can move the hyoid gently to determine tension.