The medial palpebral ligament (medial canthal tendon) is a

ligament A ligament is the fibrous connective tissue that connects bones to other bones. It is also known as ''articular ligament'', ''articular larua'', ''fibrous ligament'', or ''true ligament''. Other ligaments in the body include the: * Peritoneal l ...

of the

face The face is the front of an animal's head that features the eyes, nose and mouth, and through which animals express many of their emotions. The face is crucial for human identity, and damage such as scarring or developmental deformities may aff ...

. It attaches to the frontal process of the

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...

, the

lacrimal groove On the nasal surface of the body of the maxilla, in front of the opening of the sinus is a deep groove, the lacrimal groove (or lacrimal sulcus), which is converted into the nasolacrimal canal, by the lacrimal bone and inferior nasal concha; this ...

, and the tarsus of each eyelid. It has a superficial (anterior) and a deep (posterior) layer, with many surrounding attachments. It connects the medial canthus of each eyelid to the medial part of the

orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as ...

. It is a useful point of fixation during eyelid

reconstructive surgery Reconstructive surgery is surgery performed to restore normal appearance and function to body parts malformed by a disease or medical condition. Description Reconstructive surgery is a term with training, clinical, and reimbursement implicat ...

Structure

The anterior attachment of the medial palpebral ligament is to the frontal process of the

in front of the

(near the

nasal bone The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face and by their junction, form the bridge of the upper one third of the nose. Ea ...

and the

frontal bone The frontal bone is a bone in the human skull. The bone consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, ...

), and its posterior attachment is the lacrimal bone. Crossing the lacrimal sac, it divides into two parts, upper and lower, each attached to the medial end of the corresponding tarsus of each eyelid. As the ligament crosses the lacrimal sac, a strong aponeurotic lamina is given off from its posterior surface; this expands over the sac, and is attached to the posterior lacrimal crest. The medial palpebral ligament consists of a superficial (anterior) and a deep (posterior) layer. The superficial layer has a length of around 9.6 mm, a width of around 2.4 mm, and a thickness of around 4.5 mm. The deep layer has a length of around 3.7, a width of around 2.9, and a thickness of around 0.3 mm. Together, these have a strength of around 17

newtons The newton (symbol: N) is the unit of force in the International System of Units (SI). It is defined as 1 kg⋅m/s, the force which gives a mass of 1 kilogram an acceleration of 1 metre per second per second. It is named after Isaac Newton in r ...

, with most of this strength from the superficial layer.

Relations

The superior branch of the

medial palpebral artery The medial palpebral arteries (internal palpebral arteries) are arteries of the head that contribute arterial blood supply to the eyelids. They are derived from the ophthalmic artery; a single medial palpebral artery issues from the ophthalmic art ...

runs directly behind the medial palpebral ligament. Branches of the

facial nerve The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste ...

, particularly the buccal branches, pass upwards over the medial palpebral ligament to reach the

nose A nose is a protuberance in vertebrates that houses the nostrils, or nares, which receive and expel air for respiration alongside the mouth. Behind the nose are the olfactory mucosa and the sinuses. Behind the nasal cavity, air next passe ...

Function

The medial palpebral ligament connects the medial canthus of each eyelid to the medial part of the

Clinical significance

The medial palpebral ligament can be used as a point of fixation during eyelid

, allowing for normal blinking.

History

The medial palpebral ligament has also been known as the medial canthal tendon. Some consider it to be a

tendon A tendon or sinew is a tough, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its ability ...

of the lacrimal part of the orbicularis oculi muscle.

References